Androgens are physiologically important in the development in male secondary sex characteristics and testicular function. Androgens also have a general anabolic effect. Testosterone has its effect after binding to a specific

androgen receptor. The androgen-receptor complex then binds to a specific androgen responsive element on the DNA in the nucleus, which stimulates the transcription of certain genes.

Hypopituitarism and hypogonadism are the main indications for androgen therapy. Intramuscular administration is 250 mg every 3 weeks. However, this injection results in very high testosterone levels immediately after injection and very low levels just prior to the next injection. Oral administration of testosterone equivalents is usually 120-160 mg daily. The new form of administration via the skin results in the most physiological levels of testosterone.